1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. In addition, the present invention relates to a process, a machine, manufacture, or a composition of matter. In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a memory device, a driving method thereof, or a manufacturing method thereof. In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a storage device, a driving method thereof, or a manufacturing method thereof.
2. Description of the Related Art
A metal oxide having semiconductor characteristics called an oxide semiconductor has attracted attention. The metal oxide is used for various applications. For example, indium oxide, which is a well-known metal oxide, is used for a light-transmitting pixel electrode in a liquid crystal display device, a light-emitting device, or the like. Examples of such metal oxides having semiconductor characteristics include tungsten oxide, tin oxide, indium oxide, and zinc oxide. Transistors in each of which a channel formation region is formed using such a metal oxide having semiconductor characteristics have been known (Patent Documents 1 and 2).